Scientists using the Mast Camera aboard NASA’s Curiosity Mars rover have captured a night-sky image of two minor planets Ceres and Vesta, and one of the two Red Planet’s natural satellites, Deimos.
This false-color image shows minor planets Ceres and Vesta, Martian moons Phobos and Deimos, planets Jupiter and Saturn, as seen by NASA’s Curiosity Mars rover. Image credit: NASA / JPL-Caltech / MSSS / Texas A&M.
Ceres, a minor planet with a diameter of about 950 km, is the largest object in the main asteroid belt. Vesta is the third-largest object in the asteroid belt. Its diameter is about 563 km.
These objects are the target of NASA’s Dawn mission, which orbited Vesta in 2011 and 2012 and is on its way to begin orbiting Ceres in 2015.
Deimos is the smaller of Mars’ two moons with a mean radius of about 6 km. It orbits around Mars with a period of 30 hours at a distance of about 23,460 km.
Curiosity rover’s camera imaged Ceres, Vesta and Deimos after nightfall on April 20, 2014, or the 606th Martian sol. In other camera pointings the same night, the Curiosity’s camera also imaged Phobos and the planets Jupiter and Saturn.
Dr Mark Lemmon from Texas A&M University, a Curiosity team member, explained: “this imaging was part of an experiment checking the opacity of the atmosphere at night in Curiosity’s location on Mars, where water-ice clouds and hazes develop during this season.”
In the main portion of the new image, Vesta, Ceres and three stars appear as short streaks due to the duration of a 12-second exposure.
The background is detector noise, limiting what we can see to magnitude 6 or 7, much like normal human eyesight.
Vesta, Ceres and three stars would be visible to someone of normal eyesight standing on Mars.
Specks are effects of cosmic rays striking the camera’s light detector.
“The two Martian moons were the main targets that night, but we chose a time when one of the moons was near Ceres and Vesta in the sky,” Dr Lemmon said.
Three insets show Phobos, Jupiter and Saturn at exposures of 0.5 second each.
Deimos was much brighter than the visible stars, Vesta and Ceres in the same part of the sky, in the main image.
The circular inset covers a patch of sky the size that Earth’s full moon appears to observers on Earth.
At the center of that circular inset, Deimos appears at its correct location in the sky, in a 0.25 second exposure.
